Low-voltage electrical devices, such as for example switches circuit-breakers and disconnectors, are, as is known, devices used generally in electrical systems the operating voltage of which generally reaches up to 1000 V. It is likewise known that for correct functioning of such devices it is necessary to envisage and carry out periodic interventions of inspection and maintenance.
The interventions of inspection envisage checking of the state and functionality of the components in order to choose the type of intervention of maintenance to carry out. The maintenance interventions can be divided principally into ones of a conservative type and ones of a replacement type. In interventions of a conservative type, operations are carried out that substantially involve adjustment, calibration and setting, cleaning and regeneration of one or more components constituting the device in order to restore them to optimal operating conditions. In interventions of a replacement type, instead, replacement is made of one or more components that, following upon operation of the device, have undergone alterations such as to jeopardize their functionality irreversibly.
The configuration of current electrical devices is far from conducive to either of the types of maintenance just referred to. The components making up the devices are in fact connected to one another according to a well-defined sequence of assembly. This aspect entails that the possible regeneration and/or replacement of one of the components assembled at the start of the sequence imposes as a consequence dismantling and subsequent re-assembly of a large number of the components.
Low-voltage circuit-breakers, for example, comprise, as is known, one or more seats in which one or more fixed contacts are housed that are to be connected to corresponding mobile contacts in the proximity of an arc chamber. An appropriate kinematic chain enables movement of the mobile contacts.
Traditionally, the fixed contacts are inserted and positioned within the respective seats before the mobile contacts and before the components of the kinematic chain. It is therefore understandable how, in the current state of the art, possible operations of maintenance carried out on the fixed contacts, for example of a replacement nature, impose the need to dismantle numerous functional parts of the devices such as, for example, mobile contacts, kinematic chains and arc chambers.
Some solutions present on the market are conducive to operations of inspection, i.e. checking of the conditions of the circuit-breakers. In some cases, for example, removable grills are used, located on the outer surface of the devices in the proximity of the arc chamber or arc chambers. Removal of these grills enables, in the best of cases, removal of the arc chambers, but does not facilitate or in any case is not effectively conducive to possible maintenance interventions. In particular, there remain prevented interventions of a replacement type on the fixed contacts. The very operations of inspection and conservative maintenance can be carried out only in a partial and approximate way, on account of the limited space and angle of access to the fixed and/or mobile contacts.
There is therefore the need to have available electrical devices for low-voltage applications, that will enable to overcome the previously cited drawbacks.